Question

in a lab experiment to obtain the molar mass of a voltaile liquid, the following data is obtained:

volume of flask=225ml
mass of flask=77.834gms
mass of flask+gas=78.416gms
temperature=100 degrees celsius
pressure=714 torr

What is the molar mass of the liquid?

A)11.1 g/mol
B)22.6 g/mol
C)84.3 g/mol
D)99.2 g/mol

please help with working out this problem.

Answer 1

Use PV = nRT
Calculate n = number of moles of gas.

Then mols = g/molar mass
You know moles from the above calculation, you know grams (flask + gas - flask), solve for molar mass.

Answer 2

wow
didnt think of it that way.
thanks a lot
=)